package huawei.exam2;

import java.util.*;

/**
 * @author : Rookie
 * @description :
 * @date : 2023/6/10
 */
public class HJ34 {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        String input = in.nextLine();
        List<Character> characters = new ArrayList<>(input.length());
        for (int i = 0; i < input.length(); i++) {
            char c = input.charAt(i);
            characters.add(c);
        }
        characters.stream().sorted().forEach(System.out::print);
    }
}
